Browsing by Subject "air quality"

Now showing 1 - 8 of 8
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    At A Glance: Sustainable Tourism Report 2014 - Air Quality and Environmental Purchasing
    (University of Minnesota Tourism Center, 2014)
    Results from 426 questionnaires collected from MN industries in 2013 regarding sustainability. Includes Air Quality and Environmental Purchasing practices, completed and ongoing. Full report available at tourism.umn.edu.
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    Data and visualizations of air quality impacts of conventional and alternative light-duty transportation in the United States
    (2014-11-25) Tessum, Christopher W; Hill, Jason D; Marshall, Julian D; julian@umn.edu; Marshall, Julian D.
    This is the supporting information for an article entitled "Life cycle air quality impacts of conventional and alternative light-duty transportation in the United States", published in the Proceedings of the National Academy of Sciences of the United States (dx.doi.org/10.1073/pnas.1406853111). The study assesses the life cycle air quality impacts on human health of 10 alternatives to conventional gasoline vehicles, including vehicles powered by diesel, natural gas, ethanol, and electricity. This supporting information is comprised of 1) A Microsoft Excel file containing emissions amounts disaggregated by life cycle stage for each scenario; 2) maps of ground-level concentrations of 13 different air pollutants attributable to each scenario; and 3) videos showing temporal variation in ground-level fine particulate matter (PM2.5) and ozone (O3) concentrations attributable to each scenario. The data here were generated using state-of-the-science air pollutant emission and transport models.
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    Dataset for "Characterization of inexpensive MOx sensor performance for trace methane detection"
    (2022-03-23) Furuta, Daniel; Sayahi, Tofigh; Li, Jinsheng; Wilson, Bruce; Presto, Albert; Li, Jiayu; lijiayu@umn.edu; Li, Jiayu; University of Minnesota BBE Air and Aerosol Sensing Group
    Laboratory calibration data for three replicates each of five types of inexpensive methane sensors in support of a study characterizing sensor suitability for atmospheric monitoring, with particular attention to sensitivity to humidity and temperature. Sensor performance from ambient levels to 10ppm was characterized with decaying methane pulses at five different temperatures. Methane, water vapor levels, and temperature were monitored with reference instruments.
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    Does Community Air Monitoring Lead to Better Environmental Policy? Evaluating AB 617 in Richmond, California
    (2024-05-01) Hunt, Samantha
    Community air monitoring, publicly-operated low-cost air monitors to gather local, real-time pollution data, is one method to potentially improve air quality. Regulatory agencies are increasingly funding community monitoring to complement sparse networks of regulatory monitors. However, data from low-cost monitors often faces challenges about data quality, contributing to monitoring data seldom leading to policy change. If community air monitoring is truly an avenue for improving air quality rather than increasing awareness, I argue this data must drive regulatory change. In California, Assembly Bill (AB) 617 created a comprehensive program of public involvement in designing plans to install additional air monitors and subsequently reduce emissions. Here, I analyze key AB 617 documents from Richmond, California to trace whether new air monitoring data is linked to strategies to reduce emissions. I find most monitoring data is not used and rarely connected to regulatory change. I also classify the types of actions within Richmond’s emissions reduction plan, finding relatively few new policies that are enforceable and ready for near-term implementation. Since community monitoring data is largely unused, changes in environmental regulation may be more likely if new regulatory monitors are installed instead. Regulators should also make it clear to community members from the outset that low-cost monitoring data will not lead to new regulation at this point. An alternative, potentially more effective method to improving air quality may be using new monitoring data to pursue change through media advocacy and direct pressure on industry rather than going through state institutions.
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    Media and Devices for Management of Airborne Contaminants
    (2023-01) Hicks, Myles Devin
    This thesis presents two projects pertaining to media and devices for the management of airborne contaminants. The projects were completed consecutively and have each been separated to their respective chapters. Investigation of the Temperature Dependent Effects in Crankcase Aerosol Control Devices Oil aerosols formed in the crankcase of reciprocating engines are a significant source of particulate matter and may lead to engine component degradation when used in closed crankcase ventilation (CV) systems or constitute a significant emission source in open CV systems. In modern CV systems, filtration or inertial separation is used to collect oil particles. These devices are highly efficient over a range of flow rates and temperatures; however, some system conditions result in a decrease in efficiency with increasing temperature in a manner not predicted by theory. Experiments were performed on a bench system that introduced atomized oil particles into a clean, pre-heated, air stream that was conveyed isothermally through a heated duct to an oven containing the removal device, either a coalescing filter or an inertial separator, followed by another heated section and an exit duct. The aerosol was sampled using identical upstream and downstream isokinetic sampling systems and characterized using a Dekati Electrical Low-Pressure Impactor (ELPI) that measured particle concentration and size in the range from 0.043 to 8.46μm aerodynamic diameter. Neither single fiber efficiency (SFE) filtration theory nor physical arguments describing the performance of the inertial separator predict a significant dependence of total and fractional efficiency and most penetrating particle size (MPPS) on temperature in the range explored here, 25 to 115°C, but in many cases our measurements show MPPS shifting to smaller size and total efficiency decreasing with increasing temperature. These observations are consistent with the hypothesis that, at device temperature, the particles being processed are smaller than the particles being measured, at room temperature. Particles shrink by evaporation as they pass through the heated sections, but cool and grow by condensation as the sample cools in the sampling lines or in the exit duct. Reported carbon number distributions of typical lubricating oils and evaporation kinetics indicate that droplets in the size range investigated may lose more than half of their mass under temperature conditions, up to 115°C, found in typical crankcase removal devices under engine high-load conditions. These droplets are in a dynamic balance with their vapors and may change during sampling and measurement. Great care must be taken in design of systems used to characterize devices intended to remove volatile droplets and interpretation of measurements made, as the size of the particles measured may not be the same as the size of particles passing through the device. Evaluation of Media and Low-Cost Gas Sensors for Indoor Air Quality Measurement The second project was motivated by increasing interest in high efficiency indoor air purification devices for control of airborne contaminants. Filtration is a commonly used method for removing particulate matter and improving air quality. An emerging field is the study of impregnated media, where the same highly efficient particle removal media can be engineered to also capture pollutant gases. We set out to evaluate the pollutant gas removal effectiveness for a set of carbon-impregnated media, where the pollutant gases under investigation were CO, CO2, NO, NO2, and SO2. Another feature of the study was that the sensors used were relatively low-cost sensors and a detailed evaluation of their performance was performed. Part of the motivation for using low-cost sensors was the possibility of using them for real-time performance of media in actual air purification devices. The goal of the study was to evaluate 3 different carbon-impregnated media and a set of 6 low-cost gas sensors on a test bench designed to determine pollutant gas concentration as well as the removal efficiency. Tests were performed at ambient temperature conditions with relative humidity controlled from 5-60%, characteristic of indoor residential or commercial conditions. Five of the sensors used were Alphasense B4 series low-cost gas sensors, for monitoring CO, SO2, NO, NO2, and a combination NO2 and ozone sensor. These were electrochemical type sensors. The sixth sensor was a non-dispersive infrared sensor for measuring CO2. The pollutant gas sensors were assessed for concentration accuracy, sensor noise, and response time. We found that sensor accuracy was acceptable under both humid and dry conditions for the NO, CO, and CO2 sensors. Concentration accuracy was also acceptable for the NO2 and SO2 sensors, though indicated concentrations did not agree with expected values during media testing. This was due to concerns with the dilution air supply. Sensor noise observed was higher than specification for CO and SO2, where SO2 encountered the greatest deviations from manufacture specification. With respect to response times, it was found that the CO2 and CO sensors were slower than manufacturer specification, the NO2 and NO2/O3 matched specification, and the NO and SO2 sensors were faster than specification. The pollutant gas removal efficiency for each gas, media, and humidity combination was calculated and presented. The influence of humidity on removal effectiveness was observed, wherein humid conditions resulted in decreased pollutant gas removal efficiency. Removal efficiencies were very low for CO and NO2. They were somewhat higher for NO, SO2, and CO2, most notably under dry conditions. This work demonstrated the efficacy of using LCGSs for media evaluation.
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    State of Sustainable Tourism in Minnesota (2007)
    (University of Minnesota Tourism Center, 2007) Schneider, Ingrid E.
    Sustainable tourism has been of increasing interest in Minnesota and beyond. However, little information on attitudes toward or actual sustainable practice implementation exists. Therefore, this project assessed the ‘state of sustainable tourism in Minnesota’ to inform program & product development.
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